Method for diagnosing gastro esophageal reflux disease

ABSTRACT

A method for diagnosing gastro esophageal reflux disease (GERD), comprising: introducing an endoscope into a stomach of a subject; measuring a pressure in the stomach while supplying gas into the stomach using the endoscope; and determining whether the subject has GERD or not based on a maximum value of the pressure and a wave pattern of a value of the pressure.

BACKGROUND

This invention relates to a method for diagnosing gastro esophageal reflux disease (GERD).

GERD is a disease caused by a reflux of content of stomach including gastric acid into esophagus. Deterioration of cardia's function causes the reflux.

Twenty four-hour pH monitoring (24-hour pH monitoring) is a method for diagnosing GERD. In 24-hour pH monitoring, a patient has a tube inserted into his or her nose for 24 hours. This tube can often cause pain. Additionally, it takes a long time to diagnose GERD by using the 24-hour pH monitoring method.

SUMMARY

Exemplary embodiments relate to a method for diagnosing GERD. The method can include introducing an endoscope into a stomach of a subject, measuring a pressure in the stomach while supplying gas into the stomach using the endoscope, and determining whether the subject has GERD or not based on a maximum value of the pressure in the stomach and a wave pattern of a value of the pressure in the stomach.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart showing a flow of the method for diagnosing GERD according to one aspect of the present invention.

FIG. 2 is a schematic diagram showing a state in which an endoscope is introduced into a stomach.

FIG. 3 shows an example of a waveform of a pressure in a healthy person's stomach.

FIG. 4 shows an example of a waveform of a pressure in a GERD patient's stomach.

FIG. 5 is a flowchart showing a flow of the method for diagnosing GERD according to an exemplary embodiment.

DETAILED DESCRIPTION

An embodiment of the present invention shall be described with reference to FIGS. 1 to 5.

FIG. 1 is a flowchart showing a flow of the method for diagnosing GERD (hereinafter, simply referred as “diagnosing method”) according to the embodiment of the present invention. First, in step S10, an operator inserts an endoscope into a subject from a natural orifice such as mouth and nose, and introduces a distal portion of the endoscope in a stomach. A known flexible endoscope can be used in this procedure.

Next, in step S20, the operator obtains a parameter of the subject while increasing pressure in the stomach by supplying gas into the stomach. Gas-supplying function of the endoscope can be used in this procedure.

Cardia starts to close when the pressure in the stomach increases. Since a healthy cardia is able to keep its closing state against a high pressure, the pressure in the stomach increases as gas is supplied into the stomach. However, in GERD patients, the pressure in the stomach does not increase more than a certain value because their malfunction of the lower esophagus sphincter (LES). The volume of the gas supplied into the stomach is set to an extent in that a body reflex of closing cardia occurs in a healthy person, which is greater than a volume supplied into a stomach in an ordinary endoscopic observation. A paper “Endoscopic appearance of the Gastroesophageal valve and competence of the cardia”, Diagnostic and Therapeutic Endoscopy, 1996, Vol. 2, pp. 147-150, reports that pressure value of a stomach when cardia opens during gas-supply is deteriorated in GERD patients.

The method focuses on this phenomenon and obtains parameters while supplying gas into a stomach. GERD can be diagnosed based on the obtained parameters.

An example of the step S10 is schematically shown in FIG. 2. An endoscope 1 inserted into the subject Pt comprises an elongated insertion portion 10, a manipulation portion 20 connected to the insertion portion, and a display portion 50 connected to the manipulation portion 20. A gas-supply mechanism 30 and a pressure measuring mechanism 40 are attached to the endoscope 1. The gas-supply mechanism 30 is connected to a first channel of the endoscope 1. A tube 41 is connected to the pressure measuring mechanism 40 and inserted into a second channel of the endoscope 1. A distal end of the tube 41 (not shown) locates in the second channel.

The aforementioned configuration makes it possible to supply gas from the endoscope 1 into the stomach St of the subject Pt and measuring pressure in the stomach St by the pressure measuring mechanism 40 using the tube 41.

The tube 41 may be protruded outside the endoscope 1 from the second channel. The tube 41 may be omitted by directly connecting the pressure measuring mechanism 40 to the second channel of the endoscope 1. Since the stomach St and the second channel communicate in this diagnosing method, a pressure value in the second channel can be used as an alternative index of the pressure in the stomach St.

The operator stops the gas supply into the stomach St when a predetermined conditions are fulfilled. If necessary, the operator aspires gas and decrease the pressure in the stomach St. Examples of the predetermined conditions can be shown as follows:

-   -   The pressure value in the stomach reaches a predetermined value.     -   A predetermined period of time elapses while the pressure value         does not reach the predetermined value.

From a viewpoint in avoiding an excess stress to a stomach and a cardia, it is preferable that the predetermined value is set equal to or less than 20 mm mercury (mmHg). The predetermined period of time may be set to 10 to 600 seconds.

After that, the operator removes the endoscope 1 from the subject Pt.

The operator obtains a maximum pressure value in the stomach in step S20. If the gas supply is stopped because the pressure value reaches the predetermined value, the maximum value becomes the predetermined value.

In step S30, the operator or another diagnose determines whether the subject Pt has GERD or not using the parameters obtained in the step S20. The step S30 may be carried out after removing the endoscope 1.

When the pressure in the stomach is used in the diagnosing method, the obtained maximum value is compared with a threshold value for example. In this case, the subject is classed as “healthy” when the maximum value is equal to or greater than the threshold value, and is classed as “suspect of GERD” when the maximum value is less than the threshold value. The threshold value can be set concerning sex, age, and body size of the subject, for example 15 mmHg to 20 mmHg.

The threshold value may be lower than the predetermined value. The threshold value may be equal to the predetermined value. The gas supply and diagnosis become easy when the predetermined value is greater than the threshold value by 1 to 5 mmHg.

The operator finally determined which of “suspect of GERD” and “healthy” the subject is classed as, by combining the aforementioned classification and more than one sub finding. The sub findings in the present embodiment are shown as follows.

a. A Waveform of the Pressure in the Stomach in Step S20

The operator obtains a change over time in the pressure in the stomach during the step S20 by the pressure measuring mechanism 40 or the like.

An example of the waveform of the pressure in a stomach in a healthy person is shown in FIG. 3. In a healthy person of normal LES function, the waveform shows a tendency of increasing to the predetermined value without decreasing after the step S20 starts.

An example of the waveform of the pressure in a stomach in a GERD patient is shown in FIG. 4. In a GERD patient of deteriorated LES function, the waveform repeats increase and decrease in a certain pressure range because cardia opens before the pressure value reaches the predetermined value. As a result, the waveform becomes flat compared to that of a healthy person.

Accordingly, the waveform of the pressure in the stomach can be used as a sub finding. Several parameters in the change over time of the pressure in a stomach can be utilized as sub findings, alternative to the waveform or combined with the waveform. Examples of the parameters can be shown as follows.

-   -   Time elapsed that the pressure in the stomach reaches the         predetermined value     -   A proportion of flat wave during the step S20     -   An average pressure value in the flat wave     -   A difference of the maximum value and the minimum value of the         pressure in the stomach (a maximum amplitude)

A maximum amplitude in a healthy person is likely to be more than twice of that in a GERD patient.

b. An Endoscopic View of Cardia in the Step S20

In the step S20, the operator orientates the distal end of the endoscope 1 to the cardiac portion and observes the cardia by the endoscope 1.

In a healthy person, the operator is able to observe that the cardia surrounding the insertion portion is firmly closed in the step S20. When the predetermined value is set as a high value, the cardia may temporally open. Even in that case, the operator is able to observe that esophagus flutters and closes from its mouth-side.

In a GERD patient, loosening and partial opening of the cardia are observed in the step S20. When the esophagus is seen through the opening, the esophagus may not flutter or may show a weak fluttering.

Accordingly, the endoscopic view of cardia during pressurizing inside the stomach can be used as a sub finding.

c. A Burp Sound in the Step S20

During the step S20, when air in the stomach leaks from the cardia, a burp sound is heard. This burp sound is generated by vibration of cardia, esophagus, pharynx, or larynx. The generated burp sound can be continuously obtained by a sensor attached to the subject Pt, such as on its neck.

Following parameters about the burp sound can be a sub findings.

-   -   Length of the burp sound: Length of the burp sound is likely to         be short in healthy person, while it is likely to be long in a         GERD patient. An elapsed time of the longest burp sound and a         ratio of a period in which the burp sound is heard in the step         S20 can be shown as an example of the parameter.     -   Volume of the burp sound: Volume of the burp sound is likely to         be high in healthy person, because a large amount of air leaks         at one time. Volume of the burp sound is likely to be low in a         GERD patient because of continuous leaking of air. A value of a         maximal volume of the burp sound or an average volume of the         burp sound can be shown as an example of the parameter. Volume         evaluation such as whether the maximal volume of the burp sound         or the average volume of the burp sound is equal to or greater         than a predetermined threshold value or not also can be shown as         an example of the parameter.

The aforementioned sub findings can be obtained during the step S20 in parallel. All the sub findings may be obtained in the step S20 and some of the sub findings may be selected for combining with the classification. The sub findings may be obtained by another gas supply which is distinct from the step S20.

An order in priority may be set to a plurality of the sub findings. The sub findings combined with the classification may be increased along the order in priority when the operator finds difficulty in the determination.

As described, the diagnosing method according to the present embodiment can be carried out by introducing an endoscope in stomach and supplying gas into the stomach by a volume greater than a volume in an ordinary endoscopic procedure. Therefore, burden and pain of a subject is extremely lower than that in the 24-hour pH monitoring.

All the information used in the diagnosis can be obtained within about ten minutes, including sub findings in the present diagnosing method. The operator is able to diagnose within an hour and it is not difficult. The present diagnosing method is far better than the 24-hour pH monitoring in this aspect.

Since the present diagnosing method is carried out using an endoscope, it can be carried out with an endoscopic observation of the mucosa of esophagus-stomach junction, continuously or in parallel. As a result, the present diagnosing method is able to diagnose not only GERD in which an inflammatory finding is seen, but also a broader gastro esophageal reflux disease including non-erosive esophageal reflux disease (NERD) in which an inflammatory finding is not seen.

The present invention is not limited to what is described. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the present invention is only limited by the scope of the appended claims.

For example, gas in the stomach may be removed partially or entirely before the step S20, in order to decrease noise in measuring pressure in the stomach or the like.

In the diagnosing method according to the present invention, whether the subject has GERD or not may be diagnosed using one or more sub findings without using the maximum pressure value in the stomach.

The step S20 and the step S30 may be carried out simultaneously or in parallel after the step S10, shown as a step S25 in FIG. 5. 

1. A method for diagnosing gastro esophageal reflux disease (GERD), comprising: inserting an endoscope into a stomach of a subject; measuring a pressure in the stomach while supplying gas into the stomach using the endoscope; determining a pressure value in the stomach including a maximum value of the pressure in the stomach and determining a waveform of the determined value of the pressure; determining whether the subject has GERD based on the maximum value of the pressure and the wave pattern of the pressure value.
 2. The method for diagnosing GERD according to claim 1, further comprising: observing a cardia of the subject by the endoscope while supplying gas into the stomach using the endoscope; and determining whether the subject has GERD based on the maximum value of the pressure, the wave pattern of a value of the pressure, and a result of a cardia observation.
 3. The method for diagnosing GERD according to claim 1, further comprising: obtaining a burp sound of the subject while supplying gas into the stomach using the endoscope; and determining whether the subject has GERD based on the maximum value of the pressure, the wave pattern of a value of the pressure, and the burp sound.
 4. The method for diagnosing GERD according to claim 1, wherein the supplying gas into the stomach using the endoscope includes supplying gas of a volume identical to a volume of gas which causes a healthy person a body reflex closing cardia.
 5. The method for diagnosing GERD according to claim 1, wherein the measuring a pressure in the stomach includes measuring a pressure in a channel of the endoscope.
 6. The method for diagnosing GERD according to claim 1, further comprising: comparing the maximum value of the pressure with a threshold value; and determining that the subject has GERD when the maximum value of the pressure is below the threshold value.
 7. The method for diagnosing GERD according to claim 1, wherein determining whether the subject has GERD is based on a volume or length of the burp sound. 